Creating an Enterprise Application Using Maven

This tutorial demonstrates how to create a simple enterprise application using NetBeans IDE and Maven archetypes.
The tutorial also provides some explanations and tips on using the IDE to create and build Maven applications.

In this tutorial you create an enterprise application that is packaged as
an EAR archive and deployed to GlassFish Server Open Source Edition 3.
You create the application using the Maven Enterprise Application archetype in the New Project wizard.
The application contains an EJB project that contains a persistent entity class,
a message-driven bean and a session bean facade for the entity.
The application also contains a web project that contains two servlets.

Using Maven in the IDE

Support for Maven is fully integrated in NetBeans IDE.
Developing a project that uses the Maven framework is nearly identical to developing a project in Ant.
However, there are some differences that are related to the way Maven builds projects and works with dependencies.
The following tips can help you avoid some problems if you are creating a Maven application for the first time.

Check your Maven settings

If this is your first Maven project you will want to check the Maven configuration settings in the Options window.
Maven is bundled with the IDE and installed when you install the IDE.

Open the Options window in the IDE (Tools > Options; NetBeans > Preferences on Mac).

Select the Java category in the Options window and click the Maven tab.

Confirm that a Maven Home is specified.

You can use the Maven version bundled with the IDE or specify the location of a
local Maven installation (requires 2.0.9 or newer).

Click OK to close the Options window.

Notes.

Maven support is automatically enabled when Java is enabled in the IDE.
You will need to enable the Java EE plugin if it is not enabled.

Update your Maven repositories

Local and remote Maven repositories are used for code completion and when building projects.
You should update the indexes for the Maven remote repositories to ensure that any artifacts you
may need are readily available when you develop your project.
You can configure how often the IDE checks for updates in the Maven tab of the Options window.
You can perform an immediate check for updates and explore your local and remote Maven repositories
in the Services window.

Choose Window > Services to open the Services window.

Expand the Maven Repositories node in the Services window.

Expand a repository node to view the artifacts.

Right-click the repository node and choose Update Index in the popup menu.

When you click Update Indexes, the IDE will check and download the most recent index for each of your Maven remote repositories.
An index represents the current state of the artifacts located in the repository and is used
to provide a reference to the artifacts that are available to your application.
By default, the IDE does not download an artifact from a repository until the artifact is explicitly required.

You can search for an artifact by right-clicking the Maven Repositories node in the Services window and choosing Find.

Notes.

Indexes are quite large and it can take some time to update them all.

If you are using NetBeans IDE 7.1 or earlier you
will need to choose Window > Other > Maven Repository Browser and click the
Update Indexes (
) at the top of the Maven Repository Browser window.

Creating the Maven Enterprise Application Project

The goal of this exercise is to create an enterprise application project
using the Maven Enterprise Application archetype bundled with the IDE.
The enterprise application archetype will also create an EJB project and a webapp project.

The IDE includes several Maven archetypes in the New Project wizard to help you quickly create common NetBeans project types
such as enterprise application projects (EAR), web application projects (WAR) and EJB module projects (JAR).
The wizard also enables you to create projects from archetypes in registered remote repositories.

Choose File > New Project (Ctrl-Shift-N; ⌘-Shift-N on Mac) from the main menu.

Select Enterprise Application from the Maven category. Click Next.

Type MavenEnterpriseApp for the the Project Name and set the Project Location.

(Optional) Modify the artifact details. Click Next.

Select GlassFish Server for the Server.

Set the Java EE Version to Java EE 6 or Java EE 7.

Select Create EJB Module and Create Web App Module. Click Finish.

When you click Finish, the IDE creates the following projects from the Maven Enterprise Application archetype.

EJB. (MavenEnterpriseApp-ejb) The EJB project generally contains the source code with the business logic of the application.
The EJB project is packaged as an EJB JAR archive.

Webapp. (MavenEnterpriseApp-web) The Webapp project generally contains the presentation layer of the application
such as JSF and JSP pages and servlets.
The Webapp project may also contain source code with business logic.
The Webapp project is packaged as a WAR archive.

Assembly. (MavenEnterpriseApp) The Assembly project is used to assemble an EAR archive from the EJB and WAR archives.
The Assembly project does not contain any sources.

Enterprise Application. (MavenEnterpriseApp-ear) The Enterprise Application project does not contain any sources.
The Enterprise Application only contains a POM file (pom.xml) with details about the modules contained
in the enterprise application.

After you create the enterprise application project, the enterprise application project will be badged if any dependencies are unavailable.
If you expand the Dependencies node for the MavenEnterpriseApp-ear project, you can see if
any required libraries are missing or not on the classpath.
The enterprise application project has dependencies on the JAR and WAR that will be packaged and available after you
compile the EJB project and the web project.
You can see that MavenEnterpriseApp-ejb
and MavenEnterpriseApp-web are listed as dependencies.

In some cases you will see a Maven icon in the status bar that you can click to run a priming build and resolve missing dependencies.

Coding the EJB Project

The EJB project contains the business logic of the application.
In this application the GlassFish container will manage transactions using the Java Transaction API (JTA).
In this tutorial you will create an entity class, a message-driven bean and a session facade for the entity class
in the EJB project.

Creating the Persistence Unit

In this exercise you create a persistence unit in the EJB project.
The persistence unit specifies the database connection details and specifies how transactions are managed.
For this application you will specify JTA in the New Persistence Unit wizard because you want the GlassFish server to manage the transactions.

To create the persistence unit, perform the following steps.

Right-click the EJB project node and choose New > Other from the popup menu to open the New File wizard.

Select Persistence Unit from the Persistence category. Click Next.

Select EclipseLink as the Persistence Provider in the New Persistence Unit dialog box.

Select a datasource (for example, select jdbc/sample if you want to use JavaDB).

The datasource jdbc/sample is bundled with the IDE when you install the IDE and the GlassFish server,
but you can specify a different datasource if you want to use a different database.

You can keep the other default options (persistence unit name, EclipseLink persistence provider).

Ensure that Use Java Transaction APIs is selected and that the Table Generation Strategy is set to Create
so that the tables based on your entity classes are created when the application is deployed. Click Finish.

When you click Finish, the IDE creates the XML file persistence.xml and opens the file in the editor.
In the Projects window, you can see that the file was created in the Other Sources > src/main/resources > META-INF directory.
The file contains details about connecting to the database and how transactions are managed.
If you click the Source tab in the editor, you can see the following details about the persistence unit.

You can see that JTA is specified as the transaction type and that the application
will use the registered datasource jdbc/sample.

Creating the Entity Class

In this exercise you will create an entity class in the EJB project to represent the objects that will be persisted to the database.
To create the NewsEntity entity class, perform the following steps.

Right-click the EJB module in the Projects window and choose New > Other to open the New File wizard.

Select Entity Class from the Persistence category. Click Next.

Type NewsEntity for the Class Name.

Type ejb for the Package and leave the Primary Key Type as Long. Click Finish.

When you click Finish, the entity class NewsEntity.java opens in the Source Editor.
In the Source Editor, add some fields by performing the following steps.

Add the following field declarations to the class.

private String title;
private String body;

Right-click in the Source Editor between the class definition and choose Insert Code (Alt-Insert; Ctrl-I on Mac) > Getter and Setter.

In the Generate Getters and Setters dialog box, select the body and title fields. Click Generate.

Save your changes to the class.

Creating the Message-Driven Bean

In this exercise you will create a message-driven bean in the EJB project.
A message-driven bean is an enterprise bean that enables the asynchronous exchange of messages.
The NewsApp application uses a message-driven bean to receive and process messages sent to the queue by a servlet in the web module.

To use a message-driven bean in an application, the connector resources used by the bean need to be registered with the server.
When you are deploying to the GlassFish server, you can create the resources directly on the server through the Admin Console
or you can create the resources on deployment by specifying the details in the glassfish-resources.xml descriptor file.
When the application is deployed to the server, the server registers the resources based on the descriptor file.
When you use the New File wizard in the IDE to create a message-driven bean,
the IDE will generate the elements in the descriptor file for you.

In a Maven project, the glassfish-resources.xml file is located in the src/main/setup directory under the project
node in the Files window.

Right-click the EJB module in the Projects window and choose New > Other to open the New File wizard.

Creating the Session Bean

In this exercise you will use a wizard to create a session bean facade for the NewsEntity entity class.
The wizard will generate create, edit and find methods that will be accessed from the servlets in the webapp project.

Right-click the EJB module and choose New > Other.

From the Persistence category, select Session Beans for Entity Classes and click Next.

Select ejb.NewsEntity from the list of available entity classes and click Add to move the class to
the Selected Entity Classes pane. Click Next.

Select ejb as the Package. Click Finish.

When you click Finish the IDE generates two session facade classes: AbstractFacade.java,
and NewsEntityFacade.java which extends the abstract facade class.
The abstract facade class defines several methods that are commonly used with entity classes.

Coding the Web Application

In this section you will create two servlets in the webapp project.

Creating the ListNews Servlet

In this exercise you will create the ListNews servlet that will be used to display a list of posted messages.
You will use annotations to inject the session facade and access the findAll method and retrieve
the posted messages.

Right-click the web module project and choose New > Servlet.

Type ListNews for the Class Name.

Type web for the Package name. Click Finish.

When you click Finish, the class ListNews.java opens in the Source Editor.

When generating the import statements, you want to import the java.util libraries.

Creating the PostMessage Servlet

In this exercise you will create the PostMessage servlet that will be used to post messages.
You will use annotations to inject the JMS resources you created directly into the servlet,
specifying the variable name and the name to which it is mapped.
You will then add the code to send the JMS message and the code for the HTML form for adding a message.

Right-click the web module project and choose New > Servlet.

Type PostMessage for the Class Name.

Select web for the Package name. Click Finish.

When you click Finish, the class PostMessage.java opens in the Source Editor.

In the Source Editor, use annotations to inject the ConnectionFactory and Queue
resources by adding the following field declarations.

Note. If the IDE does not offer javax.jms as an option, you
can search the repositories for the correct artifact by clicking the suggestion icon in the margin next to
private ConnectionFactory connectionFactory; and choosing Search Dependency at Maven Repositories.

You can use the Search in Maven Repositories dialog to locate the javaee-api-6.0 artifact that contains ConnectionFactory.

Add the following code to send the JMS messages to the processRequest method.

Note. You might need to uncomment the code if
you are using an earlier version of the IDE.

Fix your imports and save your changes.

Note. You want to import the javax.jms libraries for
Connection, ConnectionFactory, Session and Queue.

Building the Application with Maven

Now that you are finished coding the application, you can use Maven to build the enterprise application.
In this section you will build and package the projects in an EAR archive.
The EAR archive will contain an EJB JAR archive and a WAR archive.
After you create the EAR archive you can deploy the archive to the target server.

Working With Project Dependencies

In this exercise you will examine the POM (pom.xml) of the web project
and modify the POM to prevent unnecessary artifacts from being included in the WAR when packaging.
Each Maven project contains a pom.xml file that contains details about the contents of archives.
Any external libraries that are required by the project are listed as dependencies in the POM.
You can modify the POM to specify the dependencies that need to be included or should be excluded when packaging the archive.

In this application, the EJB JAR and the WAR archives will be packaged in an EAR archive.
If you look at the pom.xml of the MavenEnterpriseApp-ear project, you can see that the EJB and WAR are declared as dependencies.

If you look at the pom.xml of the web project in the editor you can see that the EJB archive is declared as a dependency
and the scope is specified as provided.
When the value of the scope element of an artifact is provided, the artifact will not be included during packaging.
The web project requires the EJB archive as a dependency, but for this application you do not want the EJB archive
to be included in the WAR during packaging because
the EJB archive will be available and provided as part of the EAR archive.

You can open pom.xml in the editor and click the Graph tab to see
a visual representation of the project dependencies.
If you are using an older version of the IDE you can right-click in pom.xml in the editor
and choose Show Dependency Graph.
You can place your cursor over an artifact to display a tooltip with the artifact details.

Perform the following steps to modify the POM of the web project to add a scope element to
the dependency on the javaee-api artifact.

Expand the Project Files node under the web project.

Double-click pom.xml to open the file in the editor.

Confirm that provided is set for the value of the <scope> for the
javaee-api artifact.

If the value is not provided you need to edit the POM to make
the following changes:

You can use the code completion in the POM editor to help you edit the file.

By declaring that the dependency is provided, Maven will not package the artifact when building the WAR archive.

Save your changes.

Building with Dependencies

The Maven build framework proceeds through a specific sequence of phases, and each phase consists of one or more goals
and can be configured to use various Maven plugins.
The Build with Dependencies menu item is mapped to the install phase of the Maven build lifecycle
and is configured to use the Reactor plugin.
When you choose Build with Dependencies in the popup menu, Maven builds the application and any required dependencies and
copies the build artifacts to the local repository.

You can modify how Maven phases and goals are mapped to menu actions in the Actions panel of the project's Properties dialog box.

To build the EAR archive, perform the following step.

Right-click the MavenEnterpriseApp-ear project node and choose Build with Dependencies.

When you build the EAR project using the Reactor plugin, the sub-projects that are dependencies of the EAR project
are built before the EAR project is built. The Output window displays the build order.

The results of the build are also displayed in the Output window.

After you build the EAR project, you can see the final EAR archive inside
the target directory under the EAR project node in the Files window.

If you used the default artifact name com.mycompany, you can use the Maven Repository Browser to
view the build artifacts by expanding com.mycompany in the Local Repository.

Deploying and Running the Application

This section describes two methods for deploying the EAR archive to the server.
You can deploy the application to the GlassFish server by using a menu action in the IDE or by
using the Deploy tool in the GlassFish Admin Console.

Deploying and Running the Application from the IDE

In this exercise you will use the Run action to deploy the EAR archive to the the GlassFish server.
After you deploy the application you will open the ListNews page of the application in your browser and add a message.

Right-click the EAR project node in the Projects window and choose Run.

When you first run the project, the database is empty and there are no messages to display.

Click Add new message.

Type a message in the form in the PostMessage servlet. Click Submit Query.

When you add a message with the PostMessage servlet, the message is sent to the
message-driven bean for writing to persistent storage, and the ListNews servlet is called to display the messages in the database.
The list of messages in the database retrieved by ListNews often does not yet contain the new message because our message service is asynchronous.

Compile on Save and Deploy on Save are enable by default on Maven projects that specify GlassFish server as the target server.
For example, if you modify a save a servlet, you can reload the servlet in the browser and view the changes without
redeploying the application.

Deploying From the GlassFish Admin Console

In this exercise you will deploy the EAR archive using the Deploy tool in the GlassFish Admin Console.

Expand the Servers node in the Services window.

Start the GlassFish server.

Right-click the GlassFish server node and choose View Admin Console to open the GlassFish Admin Console
in your browser.

Click the Applications node in the left pane of the Admin Console.

Click the Deploy button in the main pane of the Admin Console.

Click Browse to locate the EAR archive for the enterprise application.

The EAR archive is located in the target directory inside the enterprise application directory
on your local system.

Click OK.

When you click OK, the GlassFish deploy tool deploys the application.

Note. If you deploy the application using the deploy tool in the GlassFish Admin Console, you will also need to
manually create the resources that are required by the application if they do not exist.

Downloading the Solution Project

You can download the solution to this tutorial as a project in the following ways.